The Financial Post reports in its Saturday edition Amaya, which acquired PokerStars for $4.9-billion this year, tumbled $6.42 to close at $28.64 Friday after saying it was being investigated by Quebec's securities regulator. A Bloomberg dispatch to the Post says the AMF is looking into trading activities in Amaya shares in relation to the company's purchase of Oldford Group Ltd. Oldford is the parent of Rational Group Ltd., which owned and operated PokerStars. Amaya shares had been among the best performers in Canada this year. The PokerStars deal, which was announced in June, transformed Amaya into the biggest player in the $4-billion global business of on-line poker. Amaya, Canaccord Genuity Group and Manulife Financial all had offices searched by investigators on Dec. 10 as part of the probe. Amaya, based in Pointe-Claire, Que., said the investigation has had "no impact" on its business operations, employees or companies. Canaccord, Canada's largest non-bank brokerage, is "co-operating with a routine request for information," said Scott Davidson, a spokesman. News of the investigation did not sit well with investors; Canaccord shares plunged $1.17 to close Friday at $6.16 on strong volume.